Split all the steps into separate methods.
Also finished removing all references to "delivery"

You can now go through the entire checkout process although
the delivery method and payment options are simple redirects.
The order doesn't actually get placed either.  That's next on
the to-do list.

Saving a delivery address now redirects to the preview page after saving
your delivery address data in the session.

Got the dynamic importing of models working by playing with the order of
imports within the models file.

django projects